Photographic paper



W- 1933- E. P. ESSLEY 1,922,670

' PHOTOGRAPHIC PAPER Filed June 17, 1929 InUerEIZf-r: E F Essley- @MMM Patented Aug. 15, 1933 UNITED STATES PATENT OFFICE 1 Claim.

More particularly the invention relates to a non-curling photographic paper and has for its object a photographic paper which when developed will lie fiat and not blister and which will remain flat under varying atmospheric 5 conditions.

A photographic paper which will not warp or curl due to changes in atmospheric conditions is of decided advantage and has a wide field of use. It is especially true of a light weight paper since the photographs can then be bound in books without the necessity of providing any mountings. This not only avoids the expense which would be entailed in mounting each photograph but also conserves space.

Numerous efforts have been made to provide a non-curling photographic paper by coating the back side of the paper in an effort to counteract the curling effect due to the absorption of moisture by the gelatinous coating on the sensitized or front side of the paper. Generally, however, the coatingon the back side of the paper has been in the form of a layer of material of such a nature that by the application of heat it forms an adhesive for the purpose of securing the paper on a suitable mounting. Such a coating on the back side of the paper however, whether in the form of an adhesive or not, prevents the air which normally fills the interstitial spaces between the fibers of the paper, from escaping during the developing process, with the result that often the sensitized coating becomes blistered.

It is another object of the invention to provide a novel-method for producing a paper which may be preserved and used after development without the aid of any mounting and which will permit of the usual developing processes without causing any blistering or curling.

Further objects and advantages of my invention will be understood from the following detailed description of the invention.

In the drawing the figure is a sectional view illustrating the invention embodied in a light weight paper.

The invention contemplates the provision of a photographic paper 1 conditioned so as to prevent curling by treating the back side 2 of the paper with a gelatinous or other suitable substance 3 which permeates the paper. Preferably the substance is applied so that it substantially fills the interstitial spaces between the fibers of the paper and thereby saturates the paper and.

without leaving any surplus on the rear surface 5 forming an impervious coating. This tends to make the paper (having a gelatinous coating 4 on the front side for supporting the sensitized coating) somewhat homogeneous in character in respect to its reaction to changes in moisture and temperature conditions. Although it is contemplated that just suflicient gelatin may be applied to treat the paper properly without leaving any surplus thereon, the invention has been practiced successfully by applying a gelatinous substance to the back of a light weight photo graphic paper so that the substance is impregnated into the paper and thereupon scraping off all of the surplus gelatin which extended outwardly beyond the rear surface of the paper.

It is believed that this coating applied to the back of the paper either drives out substantially all of the air within the paper and thereby prevents any blistering of the sensitized surface during the developing process or otherwise because of the fact that the back surface of the paper does not have an impervious layer of the gelatinous substance thereon, any entrapped air in the paper is permitted to escape through the back surface during the developing process. It is possible that the first condition is present in papers which are usually termed light weight whereas the second condition may be present in heavier grades of paper.

The result is that by making a photographic paper in accordance with the method herein 85 disclosed a paper is provided which does not blister during development and which will re main fiat under varying atmospheric conditions.

I claim as my invention:

A non-curling and non-blistering photographic paper comprising paper having a light-sensitivematerial supporting coating on one side and having the interstitial spaces in the paper completely filled with a gelatinous substance tending to make the coated paper somewhat homogeneous in structure and free from entrained air, surplus substance being scraped from the back of the paper so as to leave the ends of the fibers exposed.

ELISHA PORTER ESSLEY. 

